【作者】 夏森林；

【导师】 张继春；

【作者基本信息】 西南交通大学 ， 岩土工程， 2013， 硕士

【摘要】 重庆南涪高速线上分布有大量的陡倾小交角软弱层状岩体小净距隧道。小净距隧道在采用钻爆法修建过程中,爆破施工在造成岩体破碎、剥离的同时,爆破产生的动荷载不可避免地也造成中隔墙岩体扰动和损伤；特别是对于陡倾小交角层状岩体小净距隧道,过大的爆破振动强度有可能破坏中隔墙的稳定。因此,进行陡倾小交角层状岩体小净距隧道弱扰动掘进爆破技术研究,对于指导陡倾小交角层状岩体小净距隧道掘进爆破施工具有重要的意义。本文以重庆涪南高速上的鸭江隧道和分水岭隧道为工程背景。结合本文的研究内容,采用了现场试验、数理统计、理论分析和工程类比等方法研究了后行洞掘进爆破地震效应；在爆破地震效应研究成果的基础上,有针对性的提出陡倾小交角层状岩体小净距隧道弱扰动掘进爆破技术；然后进行了弱扰动掘进爆破技术现场验证和应用。研究成果主要有以下几个方面。通过在鸭江隧道进行的常规掘进爆破试验研究发现：后行洞掘进爆破时,中隔墙上的振动强度分布不均,中隔墙迎爆侧的振动强度要远大于背爆侧的振动强度,通常在2-10倍左右。同一点径向振动强度要比垂向的大,一般径向振动速度峰值大约是垂向振动速度峰值的1-3倍。掌子面前、后沿隧道轴线等距处围岩的振动速度不等,后方的振动速度约是前方振动速度的1-2倍,且掌子面后方的爆破振动速度衰减较趋势掌子面前方的慢,掌子面后方的中隔墙振动存在因两侧临空而引起的放大效应,且衰减规律不能用萨道夫斯基公式描述。在同一次掘进爆破中,掏槽孔的单响药量不是最大,但是炸药单耗最高,爆破的自由面条件最差,爆破时引起的振动强度最大。控制小净距隧道爆破振动强度的关键是控制掏槽孔爆破的振动强度。同时,为保证隧道掘进施工中相邻段别的炮孔爆破不发生明显的地震波叠加,掘进爆破时各段别的微差时间应该控制在50ms以上。鸭江隧道常规爆破引起的中隔墙振动强度过大,已经超过了既定的8cm/s的标准。在常规掘进爆破试验成果的基础上,有针对性的提出了陡倾小交角层状岩体隧道弱扰动掘进爆破技术措施：先行洞和后行洞错开施工、单洞采用上下台阶法施工,掏槽孔采用孔内分段装药并微差起爆,周边采用光面爆破技术。结合背景工程现场的施工情况,进行了上台阶3.2m循环进尺的弱扰动掘进爆破设计。该爆破设计在鸭江隧道工点和分水岭隧道进行了现场掘进爆破验证和应用试验,不仅取得了较好的掘进爆破效果,而且能有效的控制爆破振动强度。同时,炸药单耗有所降低,创造了工程经济效益。鸭江隧道弱扰动掘进爆破试验中,中隔墙质点最大的振动速度峰值从常规爆破试验的11.92cm/s降低至7.47cm/s,弱扰动爆破的振动强度与常规爆破相比降低了约40%。分水岭隧道弱扰动掘进爆破试验中,中隔墙质点最大的振动速度峰值从常规爆破试验的18.99cm/s降低至7.31cm/s,弱扰动爆破的振动强度与常规爆破相比降低了约60%。并且由于弱扰动爆破方案降优化了各段位起爆的药量,使得每段的爆破振动强度都有所降低。更多还原

【Abstract】 Many small-distance tunnel with deeply dipping laminated and small angle rock body distribut throughout the high speed line of Nan-fu line in Chong Qing. During the blasting of small-distance tunnel, blasting vibration load must cause disturbance and damage of the middle wall. Especially for the small-distance tunnel with deeply dipping laminated and small angle rock body, Excessive blasting vibration may destroy the stability of middle wall. So, study on the weak disturbance drivage blasting technology for the small-distance tunnel with deeply dipping laminated and small angle rock body is very meaningful to instruct construction.Taking the Ya-jiang tunnel and watershed tunnel as specific example, the in-situ test, mathematical statistics, theoretical analysis and engineering analogy methods are used in studying excavation blasting seismic effect of the latter hole excavation blasting seismic effect. On the basis of excavation blasting seismic effect research results, weak disturbance drivage blasting technology for the small-distance tunnel with deeply dipping laminated and small angle rock body is raised. Then field test and application for weak disturbance drivage blasting technology was carried out. Research results basically has the following several aspects.Through field test on conventional excavation blasting in the Ya-jiang tunnel,We found that, When the latter tunnel excavation blasting, the vibration distribution is uneven on the middle wall. Face blasting side vibration is greater than the back side, usually around2～10times. In the same point radial vibration is bigger than the vertical, usually around1～3times. The vibrating is unequal in equidistant point of front and back between the tunnel face. The back is1-2times the vibration of the front. At the same time, the attenuation trend of vibration behind the tunnel face is slower than the front. Attenuation law cannot be described by SaDaoFu formula.In the same drivage blasting, the charge mass of the cut hole is not the biggest. Due to free surface condition, the specific consumption of charge and blasting vibration are biggest. The key of control tunnel blasting vibration is control blasting vibration of cut hole. In order to ensure the blasting seismic waves do not stack, the delay time is greater than50ms.The blasting vibration of conventional excavation blasting in the Ya-jiang tunnel is greater than8cm/s. So, the weak disturbance drivage blasting technology is raised. They contain that latter hole and first hole is stagger when building, every tunnel take the method of up and down the steps, the deck charge and delay in-hole is apply in cut hole. Smooth blasting technique is used. Combined with the construction condition of specific example, the weak disturbance drivage blasting design with3.2m footage of up step is made. Then, the demonstration and application for the design is carried in Ya-jiang tunnel and watershed tunnel. It is not only acheieved good blasting effect, but also can control the blasting vibration effectively. At the same time, specific consumption of charge is reduced, so the economic benefit of the project is directly created by this design.Through the demonstration test of weak disturbance drivage blasting in Ya-jiang tunnel, the blasting vibration reduce from11.92cm/s to7.47cm/s, the proportion is about40%. Through the application test of weak disturbance drivage blasting in watershed tunnel, the blasting vibration reduce from18.99cm/s cm/s to7.31cm/s, the proportion is about60%.Due to the charge mass of initiating section in the weak disturbance drivage blasting is decrease,the blasting vibration is weaken in every initiating section.更多还原